The purpose of this study is to determine whether treatment with the soft gelatin capsule saquinavir (SQV) in combination with ritonavir or nelfinavir and other drugs that fight HIV: delavirdine and adefovir dipivoxil, will decrease the amount of HIV virus in the blood or have an effect on the number of immune system cells. A second purpose of this study is to find out if the study drug combinations are safe and how well they are tolerated.